Roof Check 2

[VenkatKannan]

Hi All
if design the solar rooftop design attachment, can i check the roof for MWFRS wind speed or C&C Wind Speed

Thanks in Advance

 

[KootK]

Sounds like a C&C wind speed situation to me.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Ron]

Agree!

 

[VenkatKannan]

ok thanks for the reply
But the C&C wind pressure is almost 75 psf uplift (Zone 3), but usual roof wood joist is 2X6 24" O.C, how it's resist the this wind load, can some one please explain

Thanks in advance

 

[JLNJ]

Sometimes it doesn't resist the load and the roof flies off.

Just because it hasn't failed (yet) doesn't mean it won't and was properly designed. This is one of the basic principles of structural engineering.

 

[kmart30]

Question....Lets say you are designing the fastening of solar panels to an existing roof system. Based on your observations you believe the roof system is not adequate to resist the wind loads when you start your design but its not in your scope of work to analyze this. Your scope is to design the fastening to the existing members only. Where do you draw the line? Contractually its not in your scope but ethically you need to let your client know right? So if the roof flies off but your panels are still attached are you off the hook? A lawyer has an argument as you are competent enough to determine at a basic level if the existing roof is adequate or not even if its not in your scope of work...right?

 

[XR250]

Question....Lets say you are designing the fastening of solar panels to an existing roof system. Based on your observations you believe the roof system is not adequate to resist the wind loads when you start your design but its not in your scope of work to analyze this. Your scope is to design the fastening to the existing members only. Where do you draw the line? Contractually its not in your scope but ethically you need to let your client know right? So if the roof flies off but your panels are still attached are you off the hook? A lawyer has an argument as you are competent enough to determine at a basic level if the existing roof is adequate or not even if its not in your scope of work...right?

Kmart,

IMHO, if he is not adding and wind load to the roof then it is an existing condition that he is not obligated to address, Let's face it, just about any residential roof we look at does not meet code for uplift once you factor in code overhang loads, actual dead load and allowables for nails in withdrawl.

 

[hokie66]

I agree with kmart. Adding solar panels to a roof that is already not strong enough to resist the code mandated loading should require strengthening of the structure.

 

[VenkatKannan]

Thanks for the reply, i got my require point